Hitherto, there have been used recording and/or reproducing apparatuses for recording and/or reproducing data of information processing equipment by using, as a recording medium, a tape cassette in which a magnetic tape for recording information signals is wound between a pair of tape reels rotatably supported within a cassette body formed by butt-joining an upper half and a lower half.
As a tape cassette used as a recording medium of the recording and/or reproducing apparatuses of this kind, there is a tape cassette having outer (outside) shape substantially the same as that of a tape cassette within which a magnetic tape having tape width caused to be 8 mm used for recording video signals, etc. as an analog signal is accommodated.
The recording and/or reproducing apparatus for recording and/or reproducing data of information processing equipment using, as a recording medium, the tape cassette within which the magnetic tape of which tape width is caused to be 8 mm is accommodated as described above carries out recording and/or reproduction of data in the state where a magnetic tape wound between a pair of tape reels rotatably supported within a tape cassette loaded in this apparatus is caused to be slidably in contact with a rotational magnetic head device while allowing it to undergo constant velocity traveling from one tape reel serving as the supply side toward the direction of the other tape reel serving as the winding side.
In this recording and/or reproducing apparatus, as a system of allowing a magnetic tape to undergo constant velocity traveling, there are a capstan drive system and a reel drive system.
In the capstan drive system, as shown in FIG. 1, a magnetic tape 2 wound extending over a pair of tape reels 1A, 1B rotatably supported within a tape cassette is caused to be put between a capstan 3 rotating at a constant velocity and a pinch roller 4 caused to be in pressure contact with the capstan 3 so that the magnetic tape 2 is caused to undergo constant velocity traveling. In accordance with the capstan drive system, means for controlling tape tension of tension arm, etc. is disposed in a traveling path for the magnetic tape 2 to control tape tension of the traveling magnetic tape 2 to thereby conduct a control so that the magnetic tape 2 is traveled at a constant velocity. In allowing the magnetic tape 2 to undergo constant velocity traveling, a reel drive shaft 6 engaged with the other tape reel 1B serving as the winding side of the magnetic tape 2 of reel drive shafts 5, 6 provided at the recording and/or reproducing apparatus side respectively engaged with a pair of tape reels 1A, 1B is rotationally driven to rotationally operate the other tape reel 1B to allow the magnetic tape 2 to undergo winding operation onto the other tape reel 1B side.
Moreover, in the reel drive system, as shown in FIG. 2, reel drive shaft 6 engaged with the other tape reel 1B serving as the winding side of the magnetic tape 2 of reel drive shafts 5, 6 respectively engaged with a pair of tape reels 1A, 1B of the tape cassette loaded in the recording and/or reproducing apparatus is only rotationally driven to rotationally operate a pair of tape reels 1A, 1B to allow the magnetic tape 2 to undergo constant velocity traveling. In accordance with the reel drive system, in more practical sense, rotational period of the reel drive shaft 6 for allowing the other tape reel 1B to undergo rotational operation so that sum of rotational periods of the tape reel 1A serving as the supply side of the magnetic tape 2 and the other tape reel 1B serving as the winding side of the magnetic tape 2 becomes constant is controlled to thereby control traveling velocity of the magnetic tape 2, thus to realize constant velocity traveling. In accordance with the reel drive system, since the magnetic tape 2 can be traveled without allowing the magnetic tape 2 to be put between the capstan and the pinch roller, the magnetic tape can be easily traveled at a high speed (velocity). Since the reel drive system can easily carry out high speed traveling of the magnetic tape 2, this system is advantageous in the case of carrying out search operation to retrieve desired data recorded on the magnetic tape 2.
In order to realize stable constant velocity traveling of the magnetic tape 2 in this reel drive system, it is necessary to control rotation of the reel drive shaft 6 for rotationally operating the other tape reel 1B serving as the winding side so that sum of rotation periods of the tape reel 1A serving as the supply side of the magnetic tape 2 and the other tape reel 1B serving as the winding side of the magnetic tape 2 precisely becomes constant in accordance with winding quantity of the magnetic tape 2 wound on the respective tape reels 1A, 1B. Meanwhile, in the case where the magnetic tape 2 is in a deformed state such that a projection is caused to take place at a portion of the circumferential direction thereof when the magnetic tape 2 is wound with respect to respective tape reels 1A, 1B, even if there is the state where rotations of respective tape reels 1A, 1B are precisely controlled, any error would take place in the velocity of tape traveling. Namely, the reason why such unfavorable phenomenon takes place is that when the winding diameter with respect to respective tape reels 1A, 1B of the magnetic tape 2 is deformed at a portion in the circumferential direction thereof, winding quantity with respect to the tape reel 1B of the drawing or winding side from the tape reel 1A of the supply side of the magnetic tape 2 corresponding to quantities of rotation of respective tape reels 1A, 1B would be changed.
As the tape reel 1A or 1B of the tape cassette used in a recording and/or reproducing apparatus as described above, tape reel constituted as shown in FIGS. 3 and 4 is known.
In the tape reel 1A or 1B, a cylindrical reel hub 11 with which the reel drive shaft provided at the recording and/or reproducing unit side is engaged is provided at the central portion, and reel flanges 12 for supporting side edge of the magnetic tape 2 wound on the outer circumferential surface of the reel hub 11 to adjust the winding shape (put the winding shape in order) are integrally provided at both upper and lower ends of the reel hub 11.
The magnetic tape 2 adapted so that information signals are recorded thereon, which is wound on the tape reels 1A, 1B, is connected to a leader tape 13 for connection, and is connected to the reel hub 11 through the leader tape 13. A tape body 14 wound on the tape reels 1A, 1B is comprised of a connection body of the leader tape 13 and the magnetic tape 2.
At the outer circumferential portion of the reel hub 11, a fitting recessed portion 16 into which a clamp member 15 is fitted is formed. Further, the leader tape 13 to which the magnetic tape 2 is connected is fitted into the fitting recessed portion 16 along with the clamp member 15 in the state where the end portion side thereof is wound on the circumferential surface of the clamp member 15, whereby the leader tape 13 is caused to be put between the clamp member 15 and the fitting recessed portion 16 so that it is supported by the reel hub 11.
At this time, the intermediate (middle) portion of the end portion side of the leader tape 13 is supported by the clamp member 15, whereby the free end 13a side and the connecting portion 13b side of the magnetic tape 2 are respectively projected toward the outer circumferential surface 11a side of the reel hub 11 from the both sides of the clamp member 15. The outer circumferential surface 11a of the reel hub 11 serves as winding surface of the tape body 14.
Meanwhile, since the leader tape 13 is provided with a view to providing protection of fragile magnetic tape 2 to prevent occurrence of trouble or failure such as cutting, etc. to securely realize connection to the tape reels 1A, 1B, the leader tape 13 is formed by synthetic resin material having large mechanical strength as compared to the magnetic tape 2. The synthetic resin material having large mechanical strength has high rigidity and is difficult to be easily deformed. The leader tape 13 having high rigidity as stated above is adapted so that the middle portion of the free end side is supported by the clamp member 15 as shown in FIG. 3, root portions 17, 18 which are the base end portion side supported by the reel hub 11 of the free end portion 13a side and the connecting portion 13b side respectively projected toward the outer circumferential surface 11a side of the reel hub 11 from the both sides of the clamp member 15 are projected substantially vertically to the outer circumferential surface 11a as shown in FIG. 4. When the leader tape 13 is extended onto the outer circumferential surface of the clamp member 15 in this state and is further wound in a direction indicated by arrow R.sub.1 in FIGS. 4 and 5 in the state where a fixed tension is rendered so as to overlap on the free end 13a, the root portion 17 of the free end 13a side and the root portion 18 of the connecting portion 13b side are swollen so that they are projected toward the outward from the outer circumferential surface 11a of the reel hub 11. This is because the root portions 17, 18 of the leader tape 13 having high rigidity projected from the both sides of the clamp member 15 would be only curved in the state stretched from the outer circumferential surface 11a without undergoing deformation following the outer circumferential surface 11a of the reel hub 11 by the leader tape 13 wound on these root portions 17, 18 in the state where a fixed tape tension is rendered.
Since the leader tape 13 having high rigidity supported on the reel hub 11 by the clamp member 15 as described above is adapted so that the root portion 18 of the connecting portion 13b side is only curved in the state stretched from the outer circumferential surface 11a without undergoing deformation following the outer circumferential surface 11a of the reel hub 11, a gap S.sub.1 takes place between the leader tape 13 and the clamp member 15 in the vicinity of the point A.sub.1 shown in FIG. 5 in the vicinity of the root portion 18. Thus, there takes place a projection projected toward the outward of the outer circumferential surface 11a by that gap S.sub.1. In addition, also at the root portion 17 of the free end 13a side, a gap S.sub.2 similarly takes place between the leader tape 13 and the clamp member 15 also in the vicinity of the point C.sub.1 shown in FIG. 5 in the vicinity of the root portion 17. As a result, there takes place a projection projected toward the outward of the outer circumferential surface 11a by that gap S.sub.2.
When projection takes place at the root potions 17, 18 projected from the both sides of the clamp member 15 as described above, the magnetic tape 2 wound on the leader tape 13 would be also wound following the projection. Namely, the magnetic tape 2 would be wound in the eccentric state where there takes place any unevenness in the winding diameter in such a manner that the winding center is not caused to be in correspondence with center of the tape reels 1A, 1B. Further, when the magnetic tape 2 is preserved for a long time in the state where winding shape onto the reel hub 11 thereof is deformed, any deformation may take place in the magnetic tape 2 in dependency upon the state of preservation.
When any deformation takes place in the magnetic tape 2 as stated above, contact state between the magnetic tape 2 and the rotational magnetic head unit of the apparatus side does not become constant when loaded into the recording and/or reproducing apparatus to carry out recording and/or reproduction of data. When the deformed portion of the magnetic tape 2 reaches the portion on the rotational magnetic head unit, the magnetic tape 2 floats from the rotational magnetic head unit so that the magnetic tape 2 and the magnetic head are greatly spaced therebetween. As a result, this gives rise to missing, etc. of information signals subject to recording and/or reproduction. Thus, it becomes impossible to carry out recording and/or reproduction of information signals with satisfactory recording and/or reproduction characteristic.
Further, in the case where a tape cassette within which magnetic tape 2 caused to be partially deformed is accommodated is loaded into the recording and/or reproducing apparatus employing the reel drive system to carry out traveling operation of the magnetic tape 2, since the winding diameter of the magnetic tape 2 changes at the deformed portion, any change takes place in the traveling velocity of the magnetic tape 2. Namely, as the result of the fact that winding diameter with respect to respective tape reels 1A, 1B of the magnetic tape 2 changes at a portion in the circumferential direction, there changes winding quantity with respect to the tape reel 1B of the drawing or winding side from the tape reel 1A of the supply side of the magnetic tape 2 corresponding to rotation quantities of respective tape reels 1A, 1B. Thus, linear velocity of the magnetic tape 2 would be varied. When traveling velocity of the magnetic tape 2 has been varied in the reel drive system, it becomes impossible to carry out recording and/or reproduction of data with satisfactory recording and/or reproduction characteristic.